It makes me wonder what Canon's strategy is around announcing their pro gear so far in advance of availability.
That's not difficult.
Pros need a camera to do their job, so even if they just lose a camera they will replace it immediately with the best tool for the job available. Announcing future releases far in advance doesn't cost many sales, but does prevent companies being pissed off when they've just bought 20 1DSIII for their ten photographers, and they become outdated a couple of weeks later.
Amateurs can hold off buying cameras, so announcing products in advance massively hits sales as amateurs will hold off buying a new camera, if there is a new one coming in a few months time. Or just buy a Nikon if they don't already have any Canon lenses, because no consumer wants to buy a camera that they know is about to be obsolete.